CEO of the Center for a New American Security and Former Undersecretary of Defense for Policy Michèle Flournoy speaks onstage during a 'Fortune'-sponsored Most Powerful Women Summit.Paul Morigi/Getty Images

Michèle Flournoy

Michèle Flournoy was reportedly asked by Secretary of Defense James Mattis to join the department as undersecretary of defense for policy. Flournoy is the co-founder and CEO of the Center for a New American Security and previously served as undersecretary of defense for policy under Barack Obama from 2009 until 2012.

Flournoy served in a variety of senior Pentagon positions and was a distinguished research professor at the National Defense University. It was widely speculated that she would likely become secretary of defense if Hillary Clinton had won the election.

Shetold Politico that she could not return to her old position: "I am a huge admirer of Jim Mattis. ... And when he called me to ask me to consider ways to help, I had to give it due consideration. But I also knew that he needed a deputy who wouldn't be struggling every other day about whether they could be part of some of the policies that were likely to take shape."

Robert S. Harward

Lockheed Martin UAE CEO Robert S. Harward was asked by Trump to replace Michael Flynn as national security advisor. Harward is a retired navy vice admiral and former deputy commander of Central Command, which oversees U.S. Military operations in much of the Middle East and Central Asia.

He held positions of progressively greater responsibility within the Navy Seals and the special forces writ large. He served on the National Security Council and as the representative of the chairman of the Joint Chiefs of Staff to the National Counterterrorism Center.

CBS reported that he declined the position when told that he would have to keep Deputy National Security Adviser KT McFarland and could not name his own staff. The position was filled by H.R. McMaster.

Donald Trump and New Jersey Governor Chris Christie emerge from the clubhouse following their meeting at Trump International Golf Club.Drew Angerer/Getty Images

Chris Christie

On Feb. 27, 2017, Trump reportedly offered New Jersey Governor and media whipping boy Chris Christie the position of secretary of labor after Trump's first nominee withdrew his nomination; Christie reported declined.

Christie has reportedly declined multiple positions over the past few months, including ambassador to Italy and secretary of homeland security.

Rudy Giuliani

Former New York City Mayor Rudy Giuliani reportedly declined two "high level" cabinet appointments. The New York Post reported that Giuliani preferred to remain in the private sector. "Before I joined the campaign I was very involved and fulfilled by my work with my law firm and consulting firm, and I will continue that work with even more enthusiasm," Giuliani said.

It may not be coincidental that previous reports show the former mayor took money from foreign governments, including Qatar and Venezuela, along with a myriad of other financial entanglements.

There seems to be an unusually wide variety of reasons for declining senior positions in the Trump administration, ranging from honor to autonomy to pride to lack of honor. It may be quite some time before we see the full cast of characters for the world's top reality show.